• Metalloenzyme Co-factors:
• Urease:
• The historical enzyme first crystallized in 1926 by James B. Sumner (Jack bean Canavalia ensiformis urease), proving that enzymes are pure proteins.
• It is a classic Nickel-containing metalloenzyme whose catalytic active site coordinates two essential nickel ($Ni^{2+}$) ions per active subunit to catalyze the hydrolytic cleavage of urea into ammonia and $CO_2$.
• Carbonic anhydrase contains Zinc ($Zn^{2+}$).
• nalysis:
• (Urease): Correct nickel-containing enzyme.

Correct option: (1) Urease